Stabilization and use of propargyl bromide

ABSTRACT

Propargyl bromide is effectively stabilized against shock or thermal decomposition by use therewith of an environmentally acceptable inert liquid solvent that forms an azeotrope with propargyl bromide.

BACKGROUND

Propargyl bromide (3-bromopropyne) is known to be useful as a soilfumigant for control of fungi, nematodes, and undesirable plant life.See for example U.S. Pat. No. 2,794,727. For such usage it would benecessary to store and transport propargyl bromide from itsmanufacturing site to other locations and ultimately to farmlands whereit would be put to use. And, in order to utilize propargyl bromide mosteffectively as a soil fumigant it would be desirable to have the abilityto use it in pressurized dispensing systems wherein the pressurizedfumigant is injected subsurface to the soil during cultivation.

Propargyl bromide is, however, a high energy material that is sensitiveto physical shock or impact, and that is also susceptible to rapidthermal decomposition upon exposure to high temperatures or fires. Inorder to more safely produce, purify, store, transport, handle and usepropargyl bromide, it is desired to stabilize the propargyl bromideagainst physical shock and exposure to elevated temperatures both in theliquid and vapor phase especially when in a confined space. In addition,since use of propargyl bromide as a soil fumigant would often involvehaving the product housed in pressurized systems or containers so thatit can be injected into the soil, stabilization of propargyl bromideagainst physical shock and exposure to elevated temperatures whenconfined under pressure is another goal to be accomplished.

The hazardous character of propargyl bromide has been recognizedheretofore, and certain stabilizing materials have been proposed foruse. For example, as indicated in Brit. 1,132,417, propargyl bromide isshock sensitive, and when in a confined space, propargyl bromide mayignite spontaneously and decompose with explosive violence, and maydetonate. To provide stabilization, Brit. 1,132,417 indicates thatcertain solvents were effective, namely toluene, xylene, a non-cyclicether, tetrahydrofuran, dioxane, beta-ionone, and ethanol. Brit.1,132,417 further points out that many organic liquids had been triedfor the purpose of stabilizing propargyl bromide, but only a few hadbeen successful, that no firm rule had been established forpredetermining which liquids would be successful and which would not,and that among materials that were tested and found ineffective werehexane, benzene, chloroform, formamide, and light petroleum oil.

In a paper entitled “Explosibility and Stabilization of PropargylBromide”, Loss Prevention, 1967, 1, 6-9, it is noted that propargylbromide is sensitive to both shock and to temperature, and that undersuitable conditions may be detonated, and that stabilization by dilutionwas explored as a possible solution to this problem. The authors of thispaper report that at a diluent level of 15%, benzene, formamide,chloroform and hexane were judged by impact tests to be poor stabilizersfor propargyl bromide, and that diethyl ether and diisopropyl etherappeared promising but were considered less attractive than toluene,xylene, and ethylhexylsorbitol. Based on processing considerations andimpact test results, toluene and xylene were selected by the authors ofthis paper for further testing. In confinement tests toluene was judgedby them to be the material of choice, especially at a dilution level of20-30%. At present, propargyl bromide diluted with 20% of toluene isavailable as an article of commerce.

Unfortunately, toluene and xylene are both incapable of effectivelystabilizing propargyl bromide in the vapor state. Thus conditions couldbe encountered in which propargyl bromide in admixture with toluenemight nonetheless undergo explosive decomposition. Also, in order to usepropargyl bromide as a soil fumigant it is important to avoidcontaminating the soil with materials that leave residues that are notreadily broken down by naturally-occurring microorganisms in the soil.Aromatic hydrocarbons such as toluene and xylene are not environmentallyfriendly as they are not rapidly consumed by such naturally-occurringmicroorganisms.

Thus a need exists for anew, environmentally-friendly way of effectivelystabilizing propargyl bromide against both shock-induced and rapidheat-induced decomposition when in the vapor state and in the liquidstate, and especially when under confinement under pressure. Because ofthe hazardous characteristics of propargyl bromide this need exists atall stages of its existence, including production, recovery,purification, handling, storage, transportation, and use.

Another need is for a more effective, environmentally-friendly, and lesshazardous way of effecting space fumigation of enclosed spaces such asindustrial and residential buildings, and especially of bulk commoditiesinfested with or susceptible to infestation by pests, while being storedor transported in such closed spaces as bulk containers, bulk storage ortransportation vessels or bins, silos, grain elevators, shipholds, bulktransport railway or road trucks, warehouses, storage sheds, and thelike.

This invention enables fulfillment of these and other needs as well.

BRIEF SUMMARY OF THE INVENTION

It has been found that propargyl bromide can be effectively stabilizedby combining propargyl bromide with an environmentally-acceptable inertliquid solvent that forms an azeotrope with propargyl bromide, such as aparaffinic and/or cycloparaffinic hydrocarbon solvent that forms anazeotrope with propargyl bromide. By “azeotrope” is meant a mixture thatunder temperature and pressure conditions encountered at any normalstage of the life-cycle of propargyl bromide, the propargyl bromide anda stabilizing amount of the hydrocarbon when in the liquid or vaporstate remain together at all times. Thus the stabilization activityprovided by the solvents used pursuant to this invention protects thepropargyl bromide against hazardous shock-induced or thermally-induceddecompositions whether the propargyl bromide is in the liquid state orin the vapor state. And accordingly, it is now possible to produce,recover, purify, handle, store, transport, and use propargyl bromidewithout fear of disastrous consequences, such as those resulting fromrapid exothermic decomposition.

By “environmentally-acceptable” is meant that the inert liquid satisfiesor, if not yet evaluated, will satisfy the requirements for listing asan “inert” or “other ingredients” in categorized List 1, List 2, List 3,or List 4 of the Office of Pesticide Programs of the United StatesEnvironmental Protection Agency, such lists as updated Jun. 12, 2001.Such lists are incorporated herein by reference as if fully set forthherein, except that all substances on such lists which do not meet allcriteria specified herein are excluded from such lists because they areincapable or unsuitable for use in the practice of this invention.

Another embodiment of this invention is a closed container such as adrum, tank, tank car, tank trailer, or the like containing (i) asolution comprising propargyl bromide and a solvent that is compatiblewith propargyl bromide, and (ii) a headspace or vapor space within saidcontainer, wherein said headspace or vapor space contains an inert gassuch that the headspace or vapor space is devoid or substantially devoidof air and elemental oxygen. The solvent in this embodiment of theinvention can be any solvent such as those described in Brit. 1,132,417,in the above paper entitled “Explosibility and Stabilization ofPropargyl Bromide”, Loss Prevention, 1967, 1, 6-9, or U.S. Pat. No.2,794,727, such as toluene or zylene, but preferably is anenvironmentally-acceptable inert liquid solvent that forms an azeotropewith propargyl bromide. More preferably, the solvent results in thecomposition being classifiable as a “flammable liquid”, in accordancewith Recommendations on the Transport of Dangerous Goods, Manual ofTests and Criteria, 3rd Revised Edition, published by United Nations,New York and Geneva, 1999 (ISBN 92-1-139068-0).

Another aspect of this invention is the utilization of a vaporizedpropargyl bromide azeotropic composition of this invention in spacefumigation.

The various embodiments of this invention will be still further apparentfrom the ensuing description and appended claims.

FURTHER DETAILED DESCRIPTION OF THE INVENTION

This invention enables propargyl bromide to be protected from the momentof its creation until the moment of its ultimate consumption, providedthe material does not encounter some extraordinary set of conditionsalong the way. And even if the propargyl bromide encounters a dangerouscondition such as a fire during storage or transportation, a collisionduring transportation, or excessive heat and pressure buildup duringconfinement, the severity and force of the decomposition of thepropargyl bromide is greatly reduced.

Preferred compositions comprise a mixture of propargyl bromide, an inertliquid azeotropic solvent, and (i) a free radical inhibitor such as asterically-hindered phenolic compound. Such compositions have been foundto possess the additional advantage of resisting chemicaltransformation, e.g., chemical rearrangement to bromoallene, which canslowly occur during long periods of storage at ambient temperatures. Asused herein “azeotropic” means that the solvent dissolves in propargylbromide and forms an azeotrope with propargyl bromide so that astabilizing amount of the solvent remains associated with the propargylbromide at all times in both in the liquid state and in the vapor state.

Another group of preferred compositions comprise a mixture of propargylbromide, an inert liquid azeotropic solvent, and an acid scavenger, suchas epoxidized soybean oil. These compositions retain the excellentstability characteristics provided by the azeotropic solvent, andadditionally are resistant to formation of color bodies and acidcontaminants in the product.

Also preferred are compositions which comprise a mixture of propargylbromide, an inert liquid azeotropic solvent, a free radical inhibitorsuch as a sterically-hindered phenolic compound, and an acid scavenger,such as epoxidized soybean oil. These compositions retain the excellentstability characteristics provided by the azeotropic solvent, resistchemical transformation, e.g., chemical rearrangement to bromoallene,and resist formation of color bodies and acid contaminants in theproduct.

Pursuant to preferred embodiments of this invention, there is provided aprocess of preparing propargyl bromide, which process comprises reactingin a reaction zone phosphorus tribromide and propargyl alcohol in aninert liquid azeotropic solvent that forms an azeotrope with propargylbromide, to form a reaction mass containing propargyl bromide and saidazeotropic solvent, and separating a mixture consisting essentially ofpropargyl bromide and said azeotropic solvent from the reaction mass,whereby a stabilizing amount of said azeotropic solvent is present withthe propargyl bromide both in the liquid state and in the vapor phase(i) during the time the propargyl bromide is being formed and (ii)during and after the time propargyl bromide is being separated from thereaction mass. Preferably, the separated mixture of propargyl bromideand said azeotropic solvent is subjected to purification and optionallybut preferably, to subsequent formulation with at least one otheradditive component, whereby propargyl bromide and a stabilizing amountof said azeotropic solvent remain together both in the liquid state andin the vapor phase at all times during the purification and thesubsequent formulation operations. The resultant composition, whether ornot subjected to the subsequent formulation, can then be packaged,stored, transported and used, whereby propargyl bromide and astabilizing amount of said azeotropic solvent remain together both inthe liquid state and in the vapor phase at all times during any and allsuch packaging, storage, transport and/or use. Preferably, a formulationstep is carried out using (i) a free radical inhibitor such as asterically-hindered phenolic compound, or (ii) an acid scavenger, suchas epoxidized soybean oil, or both of (i) and (ii).

The term “inert” as used herein means that the solvent does notchemically react with the reactants used in producing the propargylbromide under the conditions used for producing the propargyl bromide,and does not react with the propargyl bromide during the conditions usedfor producing the propargyl bromide or during normal conditionsencountered during the recovery, purification, handling, storage,transportation, or use of the propargyl bromide.

By the term “stabilizing amount” with reference to the inert azeotropicsolvent is meant an amount of the inert azeotropic solvent that is atleast sufficient to provide a propargyl bromide composition that, if andwhen subjected in liquid form to the Bundesanstalt fur Materialprufung(BAM) Impact Test procedure as described in Example 5 hereinafter,exhibits no decomposition in any of 10 replicate tests. Although someazeotropic solvents are effective at even lower amounts, typically theminimum stabilizing amount of the azeotropic solvent combined with thepropargyl bromide will be at least about 10 wt % of the composition.Preferably, the amount used should be at least about 15 wt % and morepreferably at least about 20 wt % to provide a greater margin of safety.As a practical matter, the stabilized propargyl bromide product in theliquid state will normally not contain more than about 50 wt %, andpreferably not more than about 35 wt %, of the azeotropic solvent.Preferably, the composition when in the vapor state exists atatmospheric pressure as a composition containing at least about 10 wt %,preferably at least about 15 wt %, and more preferably at least about 20wt % of the solvent.

Still another embodiment of this invention is a method of controlling atleast one pest selected from nematodes, fungi, and undesired plantlike,which method comprises applying to said at least one pest or to thelocus thereof, or to both said at least one pest and the locus thereof,a mixture comprised of propargyl bromide and an inert liquid azeotropicsolvent. Such mixture optionally but preferably is further comprised of(i) a free radical inhibitor such as a sterically-hindered phenoliccompound, or (ii) an acid scavenger, such as epoxidized soybean oil, orboth of (i) and (ii). In conducting this embodiment of the invention,different modes of operation are available for use. One such mode is tospray the pests and/or the locus of the pests with abiocidally-effective amount of an environmentally-friendly compositionof this invention such as described above, typically in more dilutedform. Another method comprises injecting a biocidally-effective amountof an environmentally-friendly composition of this invention into thesoil, typically under increased pressure, such that the pests and theirhabitat in the soil are contacted by the composition.

Other type of pests which can be effectively controlled in anenvironmentally-friendly manner by the practice of this invention arepests which infest enclosed spaces within man-made structures. Forexample, industrial and residential buildings are typically infested,especially within enclosed wall, ceiling, and/or floor spaces, withvarious insect pests. Pursuant to this invention a biocidally-effectiveamount of an environmentally-friendly azeotropic composition of thisinvention is injected, typically under increased pressure as a vapor,fog, or fine mist into such enclosed spaces to effectively combat orcontrol the infestation of pests. In preferred embodiments of thisinvention environmentally-friendly methods are provided for effectingspace fumigation of enclosed spaces of bulk commodities infested with orsusceptible to infestation by pests, while being stored or transportedin such closed spaces as bulk containers, bulk storage or transportationvessels or bins, silos, grain elevators, shipholds, bulk transportrailway or road trucks, warehouses, storage sheds, and the like. Suchmethods comprise introducing into the enclosed space, preferably in theform of an azeotropic vapor or fog, a biocidally effective amount of acomposition comprised of propargyl bromide and anenvironmentally-acceptable inert liquid solvent that forms an azeotropewith propargyl bromide, such as a paraffinic and/or cycloparaffinichydrocarbon solvent that forms an azeotrope with propargyl bromide.

In preferred embodiments of this invention, the propargyl bromidecomposition meets the requirements for classification as a “flammableliquid”. In this connection attention is invited to Recommendations onthe Transport of Dangerous Goods, Manual of Tests and Criteria, 3rdRevised Edition, published by United Nations, New York and Geneva, 1999(ISBN 92-1-139068-0).

Various azeotropic solvents can be used in the practice of thisinvention. Non-limiting examples include n-heptane, mixed heptaneisomers, cyclohexane, methylcyclohexane, 2-methylhexane,2,4-dimethylpentane, -octane, isooctane, 2-methylheptane,2,2-dimethylhexane, isopropyl alcohol, and a mixture of cyclohexane andisopropyl alcohol. A preferred solvent mixture is composed of a mixtureof C₇₋₉ hydrocarbons (e.g, Isopar E, ExxonMobil Chemical Corporation) inadmixture with cyclohexane. A particularly preferred azeotropic solventis a mixture composed primarily of C₈ isoparaffinic hydrocarbons such asIsopar C (ExxonMobil Chemical Corporation).

As noted above, it is preferred to include an epoxide, preferably anepoxidized oil such as epoxidized soybean oil as a component of thecompositions of this invention. It is also particularly preferred tofurther include a small amount of a hindered phenol such as4-methyl-2,6-ditertbutyl phenol. Especially preferred mixtures arecomposed of about 60-70 wt % (e.g., 67.5 wt %) of propargyl bromide,about 30-35 wt % (e.g., 31 wt %) of Isopar C, about 0.5-5 wt % (e.g., 1wt %) of epoxidized soybean oil, and about 0.05-0.7 wt % (e.g., 0.5 wt%) of 4-methyl-2,6-ditertbutyl phenol.

An additional and preferred option for any of the compositions of thisinvention is the presence of an inert gas such as nitrogen, helium, orargon. This minimizes or excludes oxygen from the composition, andusually results in a further decrease of the shock sensitivity of thepropargyl bromide composition. For example, it has been discovered thatadiabatic decomposition resulting from severe impact of propargylbromide when in a confined space can be avoided by filling the headspace above the liquid with an inert gas. Nitrogen is a preferred inertgas. The inert gas can be introduced into the composition by variousmeans, such as blanketing the composition with an inert gas during itsproduction, separation, and blending operations, and keeping it in aclosed container under an inert atmosphere during storage andtransportation.

It is advantageous to include an antioxidant (which is typically a freeradical scavenger) in the composition of propargyl bromide to minimizeisomerization of the propargyl bromide. Antioxidants or free radicalscavengers that can be used with propargyl bromide include phenolicantioxidants, arylphosphites, and amines. Suitable phenolic antioxidantsare typically sterically hindered phenolic antioxidants. Suchantioxidants include, but are not limited to, 2-tert-butylphenol,2-tert-amylphenol, 2,6-diisopropylphenol, 4-methyl-2-tert-butylphenol,2,4-di-tert-butylphenol, 2,4-di-tert-butyl-5-methylphenol,2,4-di-tert-butyl-6-methylphenol, 2,6-di-tert-butyl-4-methylphenol (alsocalled BHT), 3,4-dimethyl-6-tert-butylphenol,3,6-di-tert-butyl-4-(2-methyl butyl)phenol, 2,4,6-tri-tert-butylphenol,4-tert-butylcatechol, 3-tert-butylresorcinol,methylenebis(2,6-di-tert-butylphenol),1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene,and 2,5-di-tert-butylhydroquinone. Examples of arylphosphites that canbe used are triphenylphosphite, tritolylphosphite,di(phenyl)(tolyl)phosphite, di(tolyl)(phenyl)phosphite,tri(naphthyl)phosphite, and tri(xylyl)phosphite. Amines that can be usedas free radical scavengers which can be used are typicallysterically-hindered amines. Preferred free radical scavengers aresterically hindered phenolic antioxidants. Highly preferred phenolicantioxidants are those that are U.S. Food and Drug Administration (FDA)approved, particularly when the composition is to be used for soilfumigation. Preferred hindered phenolic antioxidants are2,6-di-tert-butylphenol, methylenebis(2,6-di-tert-butylphenol), and2,6-di-tert-butyl-4-methylphenol; most preferred is2,6-di-tert-butyl-4-methylphenol. Two or more different free radicalscavengers may be used in a composition of the invention.

Acid scavengers in the composition prevent further reaction of aciddecomposition products of propargyl bromide. Suitable types of acidscavengers include epoxides and epoxidized olefinically unsaturatedoils. Examples of epoxides that can be used include, but are not limitedto, 1,2-epoxypropane, 1,2-epoxybutane, 2,3-epoxybutane, 1,2-epoxyhexane,1,2-epoxycyclohexane, 1,2-epoxyheptane, 1,2-epoxyoctane,1,2-epoxydecane, 1,2-epoxycyclododecane, and styrene oxide. Epoxidizedolefinically unsaturated oils that can be used include epoxidizedbabassu oil, epoxidized palm oil, epoxidized olive oil, epoxidizedpeanut oil, epoxidized rapeseed oil, epoxidized corn oil, epoxidizedsesame oil, epoxidized cottonseed oil, epoxidized sunflower oil,epoxidized safflower oil, epoxidized hemp oil, epoxidized linseed oil,epoxidized lard oil, epoxidized neat's foot oil, and the like.Epoxidized olefinically unsaturated oils are preferred acid scavengers.Preferred is epoxidized soybean oil. Two or more acid scavengers can beused in a composition of the invention.

In the process of preparing propargyl bromide pursuant to thisinvention, propargyl alcohol, phosphorus tribromide, a stabilizing agentA) or B), optionally with a previously known stabilizing agent, such astoluene, and an amine catalyst are components of the reaction mixture. Areaction zone is formed at any point at which propargyl alcohol andphosphorus tribromide are brought into contact. This can result in thecomponents coming together out-side of a typical reactor or reactionvessel. The reaction zone usually may be any of a variety of reactors ormixers. The reaction components can initially be brought into contactwith each other in a mixing device in proximity to, but apart from, areactor or reaction vessel. Suitable mixing devices include a staticmixer, a conduit (preferably a conduit in which there is turbulentflow), or a jet mixer that produces a high velocity effluent stream. Inall such cases, the mixing device itself in which propargyl alcohol andphosphorus tribromide first come into contact with each other is part ofthe reaction zone. Preferably, the reactants are concurrently fed into areaction zone composed of at least one reactor or mixer in which all ofthe components—whether fed individually or in any subcombination(s)—allcome together for the first time and in which the reaction to formpropargyl bromide is initiated and carried out.

After the process of preparing propargyl bromide has been completed, atleast one antioxidant and/or at least one acid scavenger may be added tothe mixture.

For the process of preparing propargyl bromide, stabilizing agent A) andstabilizing agent B) are as described above for the propargyl bromidecompositions. Preferred saturated hydrocarbons and amounts are also asdetailed above. Small amounts of toluene, one more xylene isomers, or amixture of any of these, may be present in the stabilizing agent.

Preferred saturated hydrocarbons and amounts for stabilizing agents A)and B) are as detailed above for the compositions.

The amine catalyst used in the process is normally a trihydrocarbylamine. Amines that can be used as catalysts in a process of thisinvention include triethylamine, tributylamine, triphenylamine,tricyclohexylamine, and the like. Preferred amines are trialkylamineshaving up to 4 carbon atoms per alkyl group.

The process is normally conducted at one or more temperatures in therange of about to 10 about 80° C. More preferably, the reaction isconducted in the range of about to 20 about 70° C.; most preferably, thetemperature is in the range of about to 25 about 60° C. during theprocess of the invention.

It has been found possible to achieve still further advantages inconnection with the manner in which the processes of the invention arecarried out. More particularly, by cofeeding the reaction components,including the stabilizing agent, into the reactor or reaction zone,substantial additional advantages are obtained. The advantages of suchcofeeding of the reaction components are that the temperature increasewhich happens during the reaction occurs more slowly, and that thetemperature does not rise to as high a value as it does when phosphorustribromide is added to a propargyl alcohol solution containing aminecatalyst. This in turn is less demanding on cooling equipment. Typicalhigh temperatures for a cofeed operation when adding phosphorustribromide to a propargyl alcohol solution containing amine catalyst areabout 40° C. to about 70° C.

When conducting a cofeed operation, the components should be fed so thatthe propargyl alcohol and the phosphorus tribromide contact each otherin the presence of stabilizing agent. These components may be fedseparately, or the agent may be fed in combination with the propargylalcohol, the phosphorus tribromide, or in combination with both.Propargyl alcohol and phosphorus tribromide should not be fed togetheras the same feed. The amine catalyst may be co-fed singly, with agent,with propargyl alcohol, with phosphorus tribromide, or with any two ormore of the other feeds. Cofeeding does not have an adverse effect onthe yield of propargyl bromide (as compared to yields obtained whenfeeding phosphorus tribromide to a propargyl alcohol solution containingamine catalyst).

Each of the various feeds in the cofeed operation may be continuous orintermittent. Further, there is no requirement that any of the feedsoccur simultaneously with any of the other feeds. For example, theseparate feeds need not start or end at precisely the same time.Instead, there can be a suitably short time between the start of onefeed and another, while still realizing the advantages of the cofeedoperation. The point here is that the duration of the cofeeds should besufficient to obtain the foregoing advantages, but need not be exactlycoextensive in time.

For a cofeed operation, stabilizing agent A) and stabilizing agent B)are as described above for the process of preparing propargyl bromide.Preferred saturated hydrocarbons and amounts are also as detailed above.Small amounts of toluene, one more xylene isomers, one or morenon-cyclic ethers, tetrahydrofuran, dioxane, beta-ionone, ethanol, or amixture of any of these, may be present in the stabilizing agent.Although less preferred, toluene, one more xylene isomers, one or morenon-cyclic ethers, tetrahydrofuran, dioxane, beta-ionone, ethanol, or amixture of any of these may be used as the stabilizing agent for thecofeed operation.

When distilling propargyl bromide from the crude reaction product, useof a stabilizing agent having a boiling point similar to that ofpropargyl bromide is desirable because the stabilizing agent distillswith the propargyl bromide. The presence of stabilizing agent in thevapor phase with propargyl bromide minimizes the shock sensitivity ofpropargyl bromide in the vapor phase. When a mixture of two or moresaturated hydrocarbons is used, at least one of which has a boilingpoint lower than that of propargyl bromide and at least one of which hasa boiling point higher than that of propargyl bromide, it is usuallynecessary to add more of the lower-boiling hydrocarbon(s) duringdistillation of propargyl bromide so that the lower-boilinghydrocarbon(s) does not become depleted from the mixture. Without beingbound by theory, it is believed that saturated hydrocarbons formazeotropes with propargyl bromide, which causes such agent to always bepresent with the propargyl bromide whenever it vaporizes. Theconcentration of propargyl bromide would thus never increase above theazeotrope concentration, rendering the distillation inherently safe.

In the embodiments of this invention wherein pests are combatted orcontrolled by use of a composition of this invention, anybiocidally-effective amount of the composition can be used. Such amountwill of course vary depending upon the type of pests being controlled orkilled, the location in which the pests are present, the amount and typeof commodity within the enclosed space, and the type or mode ofapplication being used. For example, where agricultural bulk or preparedcommodities such as flour, beans, wheat, corn, soy beans, barley,peanuts, cocoa beans, coffee, rice, farinaceous products, fruit,vegetables, flowers, timber, and the like are present within anappropriate enclosed space such as a storage bin, silo, grain elevator,cargo vessel, aircraft, road vehicle, etc., the amount of propargylbromide in vaporized form is preferably at least sufficient tothoroughly penetrate the contents of the enclosed space yet not leave anexcessive residue on the commodities being treated. A carrier gas, suchas nitrogen, argon, or carbon dioxide, which may be heated if desired,can be used for delivering the propargyl bromide azeotropic compositionthrough the commodity being treated. Alternatively the vaporizedpropargyl bromide azeotropic composition can be employed in a largerquantity tending to leave a larger amount of residue on the commodity,followed by a purging or aeration operation with air or an inertnon-toxic gas such as nitrogen or carbon dioxide, so as to suitablyreduce residual or virtually eliminate levels of the fumigant on thecommodity. Suitable methods for estimating fumigant residues incommodities are known and can be used if desired. See for example U.S.Pat. No. 5,069,06 1. In general, the amounts of propargyl bromide on amolar basis are comparable to amounts of methyl bromide previously usedin the same or an analogous space fumigation operation. A typical amountof active fumigant (i.e., propargyl bromide) introduced into theenclosed space is in the range of about 1 to about 10 pounds perthousand cubic feet of volume. Preferred amounts are in the range ofabout 2 to about 5 pounds per thousand cubic feet of volume. Howeverdepartures from these ranges are permissible and within the scope ofthis invention, since conditions can vary substantially from case tocase. In a preferred operation, after completion of the space fumigationstep, the enclosed space is aerated with fresh air or non-toxic gas(preferably nitrogen or carbon dioxide) and even more preferably, thepropargyl bromide is purged from the aeration gas by passing the streamthrough a suitable absorbent or other retentive substrate. Suchoperations are facilitated because of the azeotropic character of theazeotropic compositions of this invention even when in the vapor state.Procedures and apparatus similar to those used or proposed for purgingmethyl bromide from gaseous streams can be used for this purpose. Notefor example, U.S. Pat Nos. 5,505,908 and 5,904,909. In the spacefumigation processes of this invention fans or blowers can be used forpropelling the vaporized azeotropic compositions into and through theencased commodity.

EXAMPLES

The following examples are illustrative and are not to be taken aslimiting the invention.

Example 1

An 18″ spinning band distillation column was employed. A vacuum systemwas attached to the distillation setup, allowing sub-atmosphericpressures to be achieved. Approximately 50 mL of material was requiredfor each set of runs. Reflux and collection of distillate werecontrolled manually. A small amount (1-2 mL) of distillate was collectedat a high reflux ratio. Analyses were performed using proton NMRspectroscopy, and the integrated peaks were normalized.

Seven sets of runs were performed. Each set of runs used a differentsolvent or solvent system. Set 1 was a calibration run, and wasperformed using a mixture of cyclohexane and isopropanol at atmosphericpressure. The results of Set 1 are shown in Table 1. Sets 2-7 weredistillations of propargyl bromide and a solvent at different pressures.Table 2 presents the experimentally determined azeotrope compositions inthe distillate for propargyl bromide with cyclohexane (Set 2), n-heptane(Set 3), heptanes (Set 4), isooctane (Set 5), Isopar C (Set 6), andmethylcyclohexane (Set 7), respectively.

TABLE 1 Set 1 Cyclohexane Isopropanol Temp. Starting material 49.4 wt %50.6 wt % Distillate 67.3 wt % 32.7 wt % 69.6° C. Literature values* 68wt % 32 wt % 69.4° C. for distillate 67.3 wt % 32.7 wt % 69.6° C. 67 wt% 33 wt % 68.6° C. 67.0 wt % 33.0 wt % 68.8° C. *Literature values arefrom Horsley, Azeotrope III, New York.

TABLE 2 Propargyl Propargyl bromide Bromoallene alcohol Solvent Temp.Set 2 Cyclohexane Starting 50.08 wt % 0.32 wt % 49.60 wt % n/a material 81 mmHg 48.68 wt % 0.56 wt % 50.77 wt % 18.0° C. 200 mmHg 50.83 wt %0.60 wt % 48.57 wt % 35.8° C. 395 mmHg 52.66 wt % 0.52 wt % 46.82 wt %53.2° C. 755 mmHg 54.73 wt % 0.50 wt % 44.77 wt % 72.8° C. Set 3n-Heptane Starting 67.81 wt % 0.43 wt % 31.77 wt % n/a material  84 mmHg72.23 wt % 2.01 wt % 25.77 wt % 22.4° C. 205 mmHg 73.76 wt % 2.06 wt %24.18 wt % 42.3° C. 396 mmHg 74.94 wt % 1.21 wt % 23.84 wt % 59.5° C.755 mmHg 76.79 wt % 0.94 wt % 22.26 wt % 78.8° C. Set 4 Heptanes¹Starting 65.02 wt % 0.46 wt % 34.52 wt % n/a material  82 mmHg 64.81 wt% 1.25 wt % 33.94 wt % 20.1° C. 753 mmHg 68.62 wt % 1.76 wt % 29.62 wt %76.1° C. Set 5 Isooctane Starting 70.26 wt % 0.46 wt % 29.28 wt % n/amaterial  79 mmHg 66.71 wt % 1.82 wt % 31.47 wt % 20.3° C. 754 mmHg73.03 wt % 1.57 wt % 25.40 wt % 78.7° C. Set 6 Isopar C² Starting 70.03wt % 0.47 wt % 29.5 wt % n/a material  81 mmHg 66.7 wt % 1.34 wt % 32.0wt % 20.8° C. 200 mmHg 67.41 wt % 2.42 wt % 30.02 wt %   40° C. 300 mmHg69.50 wt % 1.67 wt % 28.21 wt %   51° C. 450 mmHg 71.28 wt % 1.27 wt %27.44 wt %   62° C. 761 mmHg 72.96 wt % 1.17 wt % 25.87 wt % 78.9° C.Methylcyclo- Set 7 hexane Starting 67.31 wt % 0.93 wt % 0.23 wt % 31.53wt % n/a material  81 mmHg 66.45 wt % 4.85 wt % 1.31 wt % 27.39 wt %22.2° C. 753 mmHg 71.97 wt % 4.44 wt % 2.46 wt % 21.13 wt % 79.6° C.¹Heptanes (VWR Chemical Company) contain, as determined by gaschromatography/mass spectroscopy: 36.8 area % n-heptane, 27.2 area %3-methylhexane, 19.2 area % 2-methylhexane, with the remainder beingother C₇ isomers, with traces of C₆ and C₈ compounds. ²Isopar C(ExxonMobil Company) is a mixture, predominately of C₈ isomers, and isabout 80% isooctane.

Example 2

Since propargyl bromide is both toxic and impact sensitive, thedistillation apparatus was assembled so that it could be operatedremotely, which minimized the hands-on interaction of an operator withthe distillation unit. To ensure that the propargyl bromide could not beconfined, which could have led to a violent deflagration or detonation,the apparatus was constructed of glass with Teflon (PFA & PTFE)connecting tubing. There was a one-foot space between the apparatus andthe wall of the high pressure cell so that in the event of an explosion,all damage would be contained within the cell. In addition, to keeptemperatures low, vacuum distillations were performed.

The kettle was a 5-liter jacketed round bottom flask. Heat was appliedto the kettle via a heating bath (1:1 ethylene glycol/water mixture).The heating bath temperature was 70° C. for all of the distillations inthis Example. The heating bath was placed around the wall of the highpressure cell which allowed its operation without direct exposure to thedistillation assembly. A Teflon-coated magnetic stir bar was used tohelp mix the contents of the kettle. The temperature of the kettle wasmonitored via a stainless steel thermocouple, and pressure was monitoredvia a stainless steel transducer. A 2-inch inner diametervacuum-jacketed column packed with 36 inches of 0.24-inch 316 stainlesssteel Pro-Pak packing was used for the distillations of propargylbromide from crude reaction product. For distillations of propargylbromide from toluene solution, a 100 liter flask, a glass column, andapproximately 8 feet of 0.24-inch 316 stainless steel packing (Pro-Pak®,Ace Glass Incorporated, Vineland, N.J.) were used.

The distillate was a clear, water white liquid in all distillation runs.The material from Run 1 unknowingly contained cyclohexane and wasdiscarded. During Run 3 (batch 5), a slop cut was taken (first 82 gramsof 1019 grams total distillate). The slop cut contained 0.84 wt %bromoallene, whereas the second (main) cut contained 0.082 wt %bromoallene. This run showed that it is possible to separate bromoallenefrom propargyl bromide by distillation.

Runs 1-11 were distillations of crude reaction product mixture whichcontained approximately 42 wt % propargyl bromide. The typical procedurewas to water wash the product crude at the conclusion of the reaction.The crude reaction product used in Run 9 (batch 12) was not water washedprior to distillation. The Run 9 (batch 12) material had solids presentas a result, and had a very low concentration of propargyl alcohol.During all other runs distilled from crude reaction product, propargylalcohol was a major impurity in the distillate. No propargyl alcohol wasdetected in the distillate from Run 9 (batch 12). This Run shows thatpropargyl bromide containing significantly less than 0.1 wt % propargylalcohol can be produced by using non-water-washed reaction crude.

Runs 12-15 (Batches 3, 4, 10, and 15) started with a solution containing80 wt % propargyl bromide and 20 wt % toluene (Honjo Chemical Company).Run 14 (Batch 10) was distilled after cyclohexane had been added to themixture to be distilled. For safety reasons, it was desired to neverhave propargyl bromide at high concentrations (>approximately 95%). Toaccomplish this, cyclohexane was continuously fed to the kettle. Theresults of this run proved that this is a viable technique for dilutingthe vapor phase of propargyl bromide. All of the cyclohexane fed to thecolumn ended up in the distillate. In Run 15 (Batch 15), Isopar C(mixture, predominately of C₈ isomers, about 80% isooctane; ExxonMobilCompany) was charged to the system along with the propargyl bromidesolution before the start of the distillation. Again, it was desired tonever have propargyl bromide at high concentrations (>approximately95%). Isopar C and propargyl bromide formed a minimum boiling azeotrope.rope composition of roughly 69 wt % propargyl bromide and 31 wt % IsoparC was in the distillate.

The distillations produced neat propargyl bromide (approximately 99 wt%) either solution of 80 wt% propargyl bromide plus 20 wt % toluene orfrom crude reaction mixture. Results are summarized in Table 3.

TABLE 3 Propargyl Bromo- Propargyl 1,3-dibromo- 2,3-dibromo- Run Batchbromide allene alcohol propene propene Toluene Other 1 start 1 — — — — —3028.5 g distillate 682.4 g 5.9 g 8.4 g 0 0 0.4 g 142.8 g cyclohexane 2start 2 1283.5 g 8.7 g 7.8 g 41.4 g 112.2 g 1660.5 g 3115.4 g distillate1124.2 g 7.2 g 6.9 g 0 0 1.9 g 2.1 g cyclohexane 3 start 5 1195.3 g 1.7g 5.4 g 25.0 g 62.7 g 1550.3 g 2840.5 g distillate 1011.3 g 1.46 g 4.91g 0 0 0.67 g 0.88 g HCs¹ 4 start 6 1273.3 g 0 0 31.2 g 69.9 g 1598.2 g2975.1 g distillate 860.6 g 63 g 4.0 g 0 0 0.6 g 0.6 g HCs¹, 0.4 g H₂O 5start 7 1124.4 g 0 0 27.6 g 61.7 g 1411.3 g 2627.2 g distillate 986.9 g2.64 g 5.7 g 0 0 1.8 g 0.54 g HCs¹, 0.37 g H₂O 6 start 3208 g 8 1373.0 g0 0 33.7 g 75.4 g 1723.3 g distillate 1200.8 g 8.8 g 5.9 g 0 0 1.33 g0.77 g HCs¹, 0.62 g H₂O 7 start 9 1385.0 g 16.2 g 6.3 g 36.3 g 93.3 g1754.3 g 1.1 g HCs¹, 3.6 g H₂O 3297.6 g distillate 1223.5 g 14.7 g 6.2 g0 0 1.2 g 0.7 g HCs¹, 0.3 g H₂O 8 start 2250 g 11  1002.6 g 2.3 g 4.5 g25.0 g 61.9 g 1152 g 0.2 g HCs¹, 1.6 g H₂O distillate 872.0 g 2.1 g 4.0g 0 0 1.3 g 0.4 g HCs¹, 0.2 g H₂O 9 start 2241 g 12  1042.3 g 3.3 g 0.4g 26.7 g 85.7 g 1080.4 g 0.4 g HCs¹, 1.9 g acetone distillate 907.2 g2.5 g 0 0 0 1.4 g 0.1 g HCs¹, 1.4 g acetone, 0.3 g H₂O 10  start 13 1012.9 g 11.6 g 3.0 g 25.8 g 62.9 g 1157.1 g 0.5 g HCs¹, 2.7 g H₂O2276.5 g distillate 795.1 g 9.4 g 2.3 g 0 0 0.5 g 0.2 g HCs¹ 11  start2650 g 14  1145.9 g 8.0 g 5.4 g 27.5 g 66.4 g 1395.9 g 0.8 g HCs¹distillate 920.0 g 6.9 g 4.5 g 0 0 1.9 g 6.6 g HCs¹ 12  start 3 2334.0 g13.2 g 0.6 g 0 13.2 g 578.2 g 2939.6 g distillate 1972.3 g 6.5 g trace 00 0 0.4 g THF, 0.6 g cyclohexane 13  start 3267 g 4 2594.0 g 14.7 g 0.7g 0 14.7 g 643.6 g distillate 2293.2 g 7.1 g 0 0 0 0 0.5 g THF, 0.9 gcyclohexane 14  start 1900 g 10  1501.7 g 10.7 g 0.27 g 0 8.1 g 379 g0.2 g HCs¹ distillate 1496.3 g 11.8 g 0 0 0 0.2 g 15  start 2388 g 15 1330.5 g 10.3 g 0.2 g 0 7.6 g 335.7 g 703.7 g Isopar C² distillate1017.0 g 8.0 g 7.2 g 0 0 0 460.7 g Isopar C² ¹HCs is an abbreviation forhydrocarbons. ²Isopar C (ExxonMobil Company) is a mixture, predominatelyof C₈ isomers, and is about 80% isooctane.

Example 3

Heavy walled 1.5 mL glass vials with Teflon-lined septum caps were usedto oven age three-component propargyl bromide formulations. The septumcaps were to provide a path of least resistance if a pressure build-upoccurred. No such pressure build-up was ever observed, but some of thevials leaked. In these runs, temperatures of about 50° C. were used.

Very similar decomposition rates were seen at 110° C. for the toluene,Soygold 1000, and Exxsol D80 solutions. The results in DF9 were slightlydifferent from the other solutions.

The formation of bromoallene in these solutions reached a maximum ofabout 4.5 to 5% and then its concentration decreased. The drop inconcentration of 1-bromoallene and propargyl bromide is probably theresult of the formation of oligomeric and/or polymeric material. A blacksolid could be seen at the bottom of the NMR tubes.

Other impurities were present in the solutions. The propargyl aldehydelevel was 0.1 wt %, with the maximum concentration occurring at thebeginning and decreasing with time. Other aldehydes were initially lessthan 0.4%, and decreased with time. Dibromopropenes were present asthree isomers at 1-3% after 135 hours. Propargyl alcohol and propargylchloride were both present at less than 0.1 %.

The only significant reaction occurring at 50° C. over time is theisomerization of propargyl bromide to bromoallene. After 84 days, thebromoallene level increased from 0.26% to 0.57%.

TABLE 4 Initial sample composition Propargyl Other Time Propargylbromide components Container Temp. elapsed bromide Bromoallene 72.4 wt %18.1 wt % Toluene, NMR tube 110° C.  15 hr. 71 wt % 2.3 wt % 9.5 wt %toluene-d8,  33 hr. 64 wt % 3.4 wt % 0.71 wt % bromoallene  50 hr. 57.9wt % 4.0 wt % 117 hr. 38.3 wt % 3.7 wt % 135 hr. 34.1 wt % 3.9 wt % 72.4wt % 18.1 wt % Toluene, NMR tube 110° C. 9.5 wt % toluene-d8, spargedwith N₂ 80 wt % 20 wt % Soygold¹, NMR tube 110° C.  17 hr. 73.5 wt %2.00 wt % sparged with N₂,  67 hr. 51.2 wt % 4.30 wt % 0.38 wt %bromoallene  85 hr. 43.1 wt % 4.7 wt % 146 hr. 26.8 wt % 4.8 wt % 168hr. 21.1 wt % 4.6 wt % 80 wt % 20 wt % DF#9², NMR tube 110° C.  17 hr.72.1 wt % 3.2 wt % sparged with N₂,  67 hr. 41.6 wt % 4.5 wt % 0.76 wt %bromoallene  85 hr. 33.8 wt % 4.3 wt % 146 hr. 18.8 wt % 3.4 wt % 168hr. 13.8 wt % 2.8 wt % 80 wt % 20 wt % Exxsol D80³, NMR tube 110° C.  15hr. 71.4 wt % 2.5 wt % sparged with N₂,  32 hr. 63.9 wt % 3.6 wt % 0.36wt % bromoallene  50 hr. 57.0 wt % 4.0 wt % 117 hr. 35.8 wt % 4.2 wt %135 hr. 29.4 wt % 3.9 wt % 196 hr. 15.5 wt % 3.5 wt % 81 wt % 15 wt %DF#9², glass vial  50° C. leaked; study stopped 4 wt % epoxidizedsoybean oil 68 wt % 25 wt % DF#9², glass vial  50° C. leaked; studystopped 7 wt % epoxidized soybean oil 75 wt % 20 wt % Exxsol D80³, glassvial  50° C. leaked; study stopped 5 wt % epoxidized soybean oil 68 wt %25 wt % Soygold¹, glass vial  50° C. 168 hr. 6_(—) wt % 0.2_(—) wt % 7wt % epoxidized  ˜450 6_(—) wt % 0.2_(—) wt % soybean oil,  ˜750 6_(—)wt % 0.3_(—) wt % 0.2 wt % bromoallene ˜1000 6_(—) wt % 0.3_(—) wt %˜1340 6_(—) wt % 0.5_(—) wt % ˜2000 6_(—) wt % 0.5_(—) wt % ¹Soygold1000 is a methylated soybean oil product comprised of methylated soybeanoil. ²DF#9 is a naphthalene depleted aromatic hydrocarbon fluid,obtained from ExxonMobil Chemical Corporation. ³Exxsol D80 consistsmainly of non-aromatic hydrocarbons with an IBP of 200° C. minimum and aDP of 248° C. max. It is a product of ExxonMobil Chemical Corporation.

Example 4

A group of samples was prepared, varying the amount of water,2,6-di-tert-butyl-4-methylphenol (BHT), and epoxidized soybean oil (ESO)added to each propargyl bromide solution. Mesitylene was added as aninternal standard for NMR spectroscopy. Deuterated benzene was alsoadded as an internal NMR standard. The starting compositions were madeup of 80 wt % propargyl bromide, 10 wt % mesitylene, the varying amountsof water, BHT, and ESO, and enough C₆D₆ to make the components add up tobe 100 wt %. The oven-aging experiments were conducted by sealing eachsample in an NMR tube and placing each sample in an oven, either an ovenset at 50° C. or in an oven set at 60° C. The concentration of thecomponents in the test solutions are shown in Table 5; theconcentrations of the additives for each Run are shown in Table 5. “Low”water refers to less than 0.1 wt %.

Under conditions of low water at a temperature of 50° C., the presenceof 3% ESO seems to favor the formation of 1-bromoallene. Underconditions of low water and a temperature of 60° C., the presence of 3%ESO has a beneficial effect but high BHT shows the greatest beneficialeffect, regardless of the level of ESO.

TABLE 5 Starting composition (80 wt % propargyl bromide, 10 wt %mesitylene, and C₆D₆ to reach 100 wt %) Run H₂O BMT¹ ESO² Temp.  1 low0.1 wt % 1 wt % 50° C.  2 low 0.1 wt % 3 wt % 50° C.  3 low 0.5 wt % 1wt % 50° C.  4 low 0.5 wt % 3 wt % 50° C.  5 0.1 wt % 0.1 wt % 1 wt %50° C.  6 0.1 wt % 0.1 wt % 3 wt % 50° C.  7 0.1 wt % 0.5 wt % 1 wt %50° C.  8 0.1 wt % 0.5 wt % 3 wt % 50° C.  9 low 0.1 wt % 1 wt % 60° C.10 low 0.1 wt % 3 wt % 60° C. 11 low 0.5 wt % 1 wt % 60° C. 12 low 0.5wt % 3 wt % 60° C. 13 0.1 wt % 0.1 wt % 1 wt % 60° C. 14 0.1 wt % 0.1 wt% 3 wt % 60° C. 15 0.1 wt % 0.5 wt % 1 wt % 60° C. 16 0.1 wt % 0.5 wt %3 wt % 60° C. ¹BHT is 2,6-di-tert-butyl-4-methylphenol. ²ESO isepoxidized soybean oil.

Example 5

The impact tester used in this Example was manufactured by Adolf KuhnerAG (Switzerland), and is a “Falling Hammer Test” model, MP-3. Noconcrete foundation was used to support the device. The lack of aconcrete foundation does not affect the operation of the apparatus orthe results. The impact tester has a steel cylindrical base, 280 mm indiameter and 280 mm in height. Attached to the base are two rods used toguide the 5 kg drop weight. The falling height is adjustable, with amaximum falling height of approximately 100 cm. The maximum availableimpact energy from this device is 49 J. The drop weight is equipped witha brake which automatically engages after initial impact with thesample, which prevents the weight from making multiple strikes on thesample assembly. The sample assembly, of the Bundesanstalt furMaterialprufung (BAM, Berlin) design, is recommended by the UnitedNations for testing explosives and explosive articles (Recommendationson the transport of Dangerous Goods, Manual of Tests and Criteria, 2ndrevised edition), and can be used for both solids and liquids. Thissample assembly consists of two stainless steel cylinders inserted intoa guide ring and sitting on a guide block.

Impact sensitivity was determined by loading the BAM sample assemblywith 40 microliters of sample, being careful not to encase air in theassembly, then allowing the drop weight to strike the sample assembly.In some of the runs an air bath was used to heat the entire kuhner dropweight tester. The air bath consisted of a wooden and Plexiglasenclosure containing two finned strip heaters controlled by atemperature controller. A small fan was used to circulate the air insidethe enclosure. This air bath could control the temperature to within ±1°C. A temperature of 50° C. was used.

The BAM procedure calls for six trials to be run at given drop weightand height for each sample. The sample passes the test for the givenconditions if no reaction occurs in any of the six trials. However, thestandard chosen for a sample failing was that if at least one out of tentrials results in a reaction, the sample fails the test.

A reaction was typically accompanied by an audible “bang”, smoke, fire,and/or sparks. However, some samples decomposed under impact without anyof these indicators. In these instances, a reaction occurred if theresidue in the sample assembly was that of decomposition products (blacksoot, char; significant discoloration). When neat propargyl decomposedin this device, smoke was observed along with an audible report; blackchar and soot were all that remained upon opening the test cell.

At least ten replicate experiments were performed for each entry inTables 6-8. A “yes” indicates at least one decomposition occurred, and a“no” indicates no decomposition in any of the ten replicate experiments.Table 6 presents impact testing results for sample compositions droppedfrom more than one height. Table 7 presents results for samplecompositions dropped only from a height of 100 cm. All of the datapresented in Table 7 consists of runs in which the 5 kg weight wasdropped from a height of 100 cm. Mixtures of propargyl bromide withsaturated hydrocarbons, especially cyclohexane, were less prone todecomposition.

TABLE 6 Sample composition Drop height Propargyl 10 20 30 40 60 80 90100 bromide Other components cm cm cm cm cm cm cm cm 0 wt % 100 wt % nono Nitromethane 100 wt % none yes yes yes yes yes yes 100 wt % none yesyes 80 wt % 20 wt % Toluene no no 80 wt % 20 wt % A150ND¹ no no no no no80 wt % 20 wt % Soygold no no no 1000² 80 wt % 20 wt % Isopar M³ no nono 80 wt % 20 wt % Exxsol no no no D80⁴ 80 wt % 13 wt % A150ND¹, no nono 7 wt % ESO ¹A150ND is a naphthalene depleted aromatic 150 hydrocarbonfluid. ²Soygold 1000 is a methylated soybean oil product comprised ofmethylated soybean oil ³Isopar M is a non-aromatic hydrocarbon fluidhaving a minimum IPB of 218° C. and a maximum DP of 257° C. and is aproduct of ExxonMobil Chemical Corporation. ⁴Exxsol D80 consists mainlyof non-aromatic hydrocarbons with an IBP of 200° C. minimum and a DP of248° C. max.

TABLE 7 Sample composition Propargyl Result bromide Other components 100cm 95 wt % 5 wt % Toluene no 97.5 wt % 2.5 wt % Toluene yes 95 wt % 5 wt% Exxsol D80¹ no 95 wt % 5 wt % Exxsol D80¹ no 97.5 wt % 2.5 wt % ExxsolD80¹ yes 98 wt % 2 wt % Exxsol D80¹ yes 95 wt % 5 wt % Soygold 1000² yes92.5 wt % 7.5 wt % Soygold 1000² no 95 wt % 5 wt % DF#9³ yes 92.5 wt %7.5 wt % DF#9³ no 95 wt % 5 wt % Isopar M⁴ no 97.5 wt % 2.5 wt % IsoparM⁴ yes 95 wt % 5 wt % Cyclohexane no 97.5 wt % 2.5 wt % Cyclohexane no95 wt % 5 wt % n-Heptane no 97.5 wt % 2.5 wt % n-Heptane yes 74.9 wt %10 wt % Cyclohexane, no 10 wt % Soygold 1000², 5 wt % ESO, 0.1 wt % BHT74.9 wt % 10 wt % Cyclohexane, no 10 wt % Exxsol D80¹, 5 wt % ESO, 0.1wt % BHT 74.9 wt % 10 wt % Cyclohexane, 10 wt % DF#9³, no 5 wt % ESO,0.1 wt % BHT 74.9 wt % 10 wt % Cyclohexane, 10 wt % toluene, no 5 wt %ESO, 0.1 wt % BHT 74.9 wt % 10 wt % Cyclohexane, 10 wt % Isopar E⁴, no 5wt % ESO, 0.1 wt % BHT 77 wt % 10 wt % Cyclohexane, 9.5 wt % Isopar E⁴,no 3 wt % ESO, 0.5 wt % BHT 67.5 wt % 31 wt % Isopar C⁵, 1 wt % ESO, no0.5 wt % BHT 67.5 wt % 31 wt % Isopar C⁵, 1 wt % ESO, no 0.5 wt % BHT(at 50° C.) 0 wt % 100 wt % 1,3-dichloropropene no 0 wt % 100 wt %Propargyl alcohol no ⁴Isopar E is a non-aromatic hydrocarbon fluidhaving a minimum IBP of 113° C., a 50% recovered temperature in therange of 116-128° C., and a maximum DP of 143° C. and is a product ofExxonMobil Chemical Company. ⁵Isopar C (ExxonMobil Company) is anisoparaffinic hydrocarbon mixture, predominately of C₈ isomers, andapparently contains about 80% of isooctane.

Example 6

The adiabatic compression cell and its parts were designed andfabricated by Safety Consulting Engineers, Inc. (Schaumberg, Ill.).

The adiabatic compression test cell consists of a plunger, ˜0.3 inchesin diameter, which fits into a cylindrical base. An O-ring makes anairtight seal between the plunger and the base. An aluminum rupture disk(0.020 inches thick) and a PTFE Teflon seal disk (0.039 inches thick)are used to seal the sample chamber and provide pressure relief.

Liquid sample (0.030 mL) was loaded into the bottom of the cell. The gaspresent during the adiabatic compression test was chosen by loading thecell in either the atmosphere or a nitrogen purged glovebox. The plungerwas inserted a fixed distance into the base. A drop weight of 5 kg wasused for all trials, and the drop height was varied for some samples.The drop weight was allowed to strike the plunger. Results were recordedas “go” or “no”. A “go” (reaction) is defined as an impact that producesone or more of the following phenomena: (a) audible report, (b) flame orvisible light, (c) definite evidence of smoke (not to be confused with afume), and (d) definite evidence of discoloration of the sample due todecomposition. Table 8 summarizes the results for the samples tested inair; Table 9 summarizes the results for the samples tested undernitrogen. In both Tables, the “# Go” and “# No” show how many trials ofthe total for the set had that result. For the sets using severaldifferent drop heights, a range is reported. The 50% Go/No Height is astatistically determined value at which half of trials should result in“Go” and the other half in “No”.

TABLE 8 Propargyl Other Total # 50% Go/No Set bromide components oftrials # Go # No Drop Height height Observations 2 100 wt % 0 wt % 5 5 05-10 cm <5 cm audible report, smoke, and soot 4 80 wt % 20 wt % Toluene4 4 0 5 cm <5 cm smoke and soot 5 80 wt % 20 wt % Exxsol D80¹ 10  10  05-96 cm <5 cm smoke and soot 6 80 wt % 20 wt % Soygold 1000² 4 4 0 5 cm<5 cm smoke and soot 7 80 wt % 20 wt % A150³ 7 6 1 5 cm  <5 cm⁴ smokeand soot 8 80 wt % 20 wt % Isopar M⁵ 4 4 0 5 cm <5 cm smoke and soot;faint “pop” in three trials 9 80 wt % 20 wt % Cyclohexane 4 4 0 5 cm <5cm smoke and soot; faint “pop” in two trials 10  80 wt % 13 wt %A150ND³, 5 4 1 5 cm  <5 cm⁶ smoke seen in four 7 wt % epoxidized soybeanoil trials; soot seen in two of these trials 16  74.9 wt % 10 wt %Exxsol D80¹, 10 wt % cyclohexane, 1 1 0 5 cm <5 cm faint audible report,5 wt % epoxidized soybean oil, 0.1 wt % BHT⁷ smoke, char 22  67.5 wt %31 wt % Isopar C⁸, 1 wt % epoxidized soybean 4 4 0 5 & 96 cm <5 cm faintaudible report, oil, smoke, char 0.5 wt % BHT⁷ 11  64.9 wt % 20 wt %Exxsol D80¹, 10 wt % cyclohexane, 4 4 0 5 cm <5 cm smoke and soot; 5 wt% epoxidized soybean oil, 0.1 wt % BHT⁷ faint “pop” 20  50 wt % 50 wt %Exxsol D80¹ 1 1 0 5 cm <5 cm faint audible report, smoke, char 17  0 wt% 100 wt % Soygold 1000² 4 2 2 5-96 cm “Go” as low “Go” trials: as 10 cmwhite smoke, discoloration of liquid 18  0 wt % 100 wt % Cyclohexane 2 20 5 & 10 cm “Go” as low smoke, as 5 cm discoloration of liquid 1 0 wt %Nitromethane (99+%; Aldrich) 21  12  9 6.5-12.5 cm 7.7 cm all “Go”trials: audible report and smoke; five of these burst the rupture disk⁴One test out of seven was a “no” from 5.0 cm. ⁶One test out of five wasa “no” from 5.0 cm.

TABLE 9 Sample composition (N₂ atm.) Propargyl Total # 50% Go/No Setbromide Other components of trials # Go # No Drop height height Comments 3 100 wt % 0 wt % 14 2 12 90.2 & 96 cm ≧96 cm¹ all “Go” results:audible report, smoke, and soot 12 74.9 wt % 10 wt % toluene, 10 wt %cyclohexane, 10 0 10 96 cm >96 cm two trials showed 5 wt % epoxidizedsoybean oil, 0.1 wt % BHT² slight discoloration 13 74.9 wt % 10 wt %Soygold 1000³, 10 wt % cyclohexane, 10 0 10 96 cm >96 cm — 5 wt %epoxidized soybean oil, 0.1 wt % BHT² 14 74.9 wt % 10 wt % Exxsol D80⁴,10 wt % cyclohexane, 10 0 10 96 cm >96 cm — 5 wt % epoxidized soybeanoil, 0.1 wt % BHT² 15 74.9 wt % 10 wt % DF#9⁵, 10 wt % cyclohexane, 10 010 96 cm >96 cm — 5 wt % epoxidized soybean oil, 0.1 wt % BHT² 21 67.5wt % 31 wt % Isopar C⁶, 1 wt % epoxidized soybean oil,  4 0  4 96 cm >96cm Faint audible 0.5 wt % BHT² report, smoke, and soot ¹At 96.0 cm, twoof eleven experiments resulted in “go”. The remaining nine experiments,and an additional two experiments at 90.2 cm, resulted in “no”.

Example 7

Tests were performed to determine the initiation sensitivity ofpropargyl bromide and propargyl bromide formulations to sudden gascompression (adiabatic compression). The instantaneous compression ofair in the test cell simulates various conditions. Such conditionsinclude pressure waves from an opening/closing valve or a pump (pumpripple); a water hammer; the presence of air and/or gas bubbles inliquid.

An adiabatic compression cell was used in conjunction with a Bureau ofMines (BOM) drop impact tester. If a reaction occurred with a dropheight less than 100 cm, the material was too hazardous to pump. For alltrials, the drop weight was 5 kg; sample size was 2 drops (˜30˜40 mg).Some trials were run under nitrogen (to minimize or exclude oxygen). A“yes” (GO) result indicated that decomposition occurred, while a “no”result (NO GO) indicated that no decomposition occurred. Results fortests under air are summarized in Table 10; Table 11 summarizes resultsfor test conducted under nitrogen.

TABLE 10 Sample composition Propargyl Other Drop bromide components Atm.height Result 100 wt % 0 wt % air 150 cm yes; smoke, soot 100 cm yes;smoke, soot; rupture disc burst  80 wt % 20 wt % air 150 cm yes;soot-like residue toluene 125 cm yes; soot-like residue 100 cm yes;smoke and soot 100 cm yes; soot-like residue  75 cm yes; soot-likeresidue  60 cm yes; soot-like residue  40 cm yes; soot-like residue  30cm yes; soot-like residue  20 cm yes; soot-like residue  15 cm yes;soot-like residue  10 cm yes; soot-like residue  70 wt % 23 wt % air 100cm yes; soot-like residue Aromatic 150¹,  60 cm yes; soot-like residue 7wt %  40 cm yes; soot-like residue epoxidized  30 cm yes; soot-likeresidue soybean oil  20 cm yes; soot-like residue  10 cm no  0 wt %nitromethane* air  75 cm yes  60 cm yes  30 cm yes  20 cm yes  15 cm no 15 cm no  15 cm yes ¹Aromatic 150 is more than 99% purenaphthalene-depleted C₇₋₉ aromatic hydrocarbons (CAS 70693-06-0). *Foreach “yes” result, the rupture disc burst and/or the piston forcefullypushed out the compression cell.

TABLE 11 Sample composition At- Propargyl Other mos- bromide componentsphere Drop height Result 100 wt %  0 wt % partial 100 cm yes reduction 80 cm yes of O₂  60 cm yes with N₂  40 cm yes  35 cm yes  25 cm yes  20cm yes  15 cm no  10 cm yes  10 cm yes 100 wt %  0 wt % N₂  30 cm no  50cm no  75 cm no 100 cm no 100 cm no 100 cm no 150 cm no; slightdiscoloration of liquid sample 150 cm no; slight discoloration of liquidsample 150 cm no; slight discoloration of liquid sample 125 cm no  80 wt% 20 wt % N₂ 100 cm no toluene 100 cm no 100 cm no 125 cm no 150 cm no;slight discoloration of liquid sample 150 cm no; slight discoloration ofliquid sample 150 cm no; slight discoloration of liquid sample 150 cmno; slight discoloration of liquid sample

Example 8

Differential scanning calorimetry (DSC) tests were performed onpropargyl bromide formulations to determine the combustion (exothermicpeak) temperature and melting (endothermic) temperature of eachformulation. A Differential Scanning Calorimeter (TA Instruments, model2910) was utilized. The material was placed into the sample holder ofthe calorimeter, and heated at a rate of 10° C. per minute. For thisheating rate, the temperature at which maximum heat output rate occurredwas defined as the peak exothermic temperature of the sample. Both theonset temperature and maximum heat output rate temperature wererecorded. If the onset exotherm is less than 100° C., the material isregarded as being too hazardous to ship. The onset and exothermic peaktemperature results for the propargyl bromide formulations tested areshown in Table 12.

TABLE 12 Sample composition Onset Peak Propargyl Tem- Exothermic bromideOther components perature Temperature 100 wt % 0 wt % 233° C. 299° C. 80wt % 16 wt % Aromatic 150, 226° C. 355° C. 4 wt % epoxidized soybean oil80 wt % 13 wt % Aromatic 150, 226° C. 310° C. 7 wt % epoxidized soybeanoil 70 wt % 26 wt % Aromatic 150, 226° C. 306° C. 4 wt % epoxidizedsoybean oil 70 wt % 23 wt % Aromatic 150, 225° C. 306° C. 7 wt %epoxidized soybean oil 100 wt % 0 wt % 173° C. 245° C.

Example 9

Propargyl bromide and formulations thereof underwent testing todetermine their sensitivity to intensive heat under confinement,sometimes called a Koenen test. An aperture disc with an adjustableorifice diameter was used; the diameter was set to 1.0 mm for all runs.The test results are assessed on the basis of the tube fragmentationtype and limiting diameter of the orifice allowing the by-product toescape under test conditions when subjected to intense heat. UnderUnited Nations standards, the result is considered positive if thesubstance shows violent effect on heating under confinement when thelimiting diameter of the orifice disk is 2.0 mm or larger. The result isconsidered negative if the substance shows no violent effect on heatingunder confinement when the limiting diameter of the orifice disk is lessthan 2.0 mm. The results are summarized in Table 13.

TABLE 13 Sample composition Overall Propargyl Other Sample Time-to- TubeResult bromide components weight Reaction Condition Explosion 37.6 g 10sec smoke unchanged, no 60 sec smoke + fire no damage 75 sec no smoke37.7 g 12 sec smoke unchanged, no 70 sec smoke + fire no damage 80 secno smoke 80 wt % 13 wt % Aromatic 150, 40.9 g 14 sec smoke unchanged, no7 wt % epoxidized 80 sec no smoke no damage soybean oil 40.5 g 12 secsmoke unchanged, no 90 sec no smoke no damage 40.8 g 13 sec smokeunchanged, no 85 sec no smoke no damage

Example 10

Propargyl bromide formulations were tested to determine theirsensitivity to detonative shock while confined in a heavy steel tube.Each formulation was placed in an uncapped steel cylinder, 4 incheslong, having a 1.5 inch outer diameter and a 0.5-inch inner diameter.The witness plate, 3 inches×3 inches×0.75 inches thick, is positioned atthe bottom end of the tube while a pentolite booster is placed at thetop end of the tube. A blasting cap is utilized to initiate the booster.The reaction is considered positive if a hole is punched through thewitness plate and/or if the steel cylinder (pipe container) isfragmented entirely. The results for the propargyl bromide formulationstested are summarized in Table 14.

TABLE 14 Sample composition Observations Propargyl Witness Steel bromideOther components Plate Tube/Pipe Results 100 wt %  0 wt % No damage notfound no and/or dent on plate 100 wt %  0 wt % No damage split half noand/or dent open on plate 80 wt % 16 wt % No damage split half noAromatic 150, and/or dent open 4 wt % on plate epoxidized soybean oil 80wt % 13 wt % No damage no visual no Aromatic 150, and/or dent damage 7wt % on plate epoxidized soybean oil 70 wt % 26 wt % No damage no visualno Aromatic 150, and/or dent damage 4 wt % on plate epoxidized soybeanoil 70 wt % 23 wt % No damage no visual no Aromatic 150, and/or dentdamage 7 wt % on plate epoxidized soybean oil  0 wt % 100 wt % H₂O Nodamage split, but no and/or dent still held on plate together

It is to be understood that the ingredients referred to by chemical nameor formula anywhere in the specification or claims hereof, whetherreferred to in the singular or plural, are identified as they existprior to coming into contact with another substance referred to bychemical name or chemical type (e.g., another reactant, a solvent, adiluent, or etc.). It matters not what preliminary chemical changes,transformations and/or reactions, if any, take place in the resultingmixture or solution or reaction medium as such changes, transformationsand/or reactions are the natural result of bringing the specifiedreactants and/or components together under the conditions called forpursuant to this disclosure. Thus the reactants and other materials areidentified as ingredients to be brought together in connection withperforming a desired chemical reaction or in forming a mixture to beused in conducting a desired reaction. Accordingly, even though theclaims hereinafter may refer to substances, components and/oringredients in the present tense (“comprises”, “is”, etc.), thereference is to the substance or ingredient as it existed at the timejust before it was first contacted, blended or mixed with one or moreother substances or ingredients in accordance with the presentdisclosure. The fact that the substance or ingredient may have lost itsoriginal identity through a chemical reaction or transformation orcomplex formation or assumption of some other chemical form during thecourse of such contacting, blending or mixing operations, is thus whollyimmaterial for an accurate understanding and appreciation of thisdisclosure and the claims thereof. Nor does reference to an ingredientby chemical name or formula exclude the possibility that during thedesired reaction itself an ingredient becomes transformed to one or moretransitory intermediates that actually enter into or otherwiseparticipate in the reaction. In short, no representation is made or isto be inferred that the named ingredients must participate in thereaction while in their original chemical composition, structure orform.

Each and every patent or other publication referred to in any portion ofthis specification is incorporated in toto into this disclosure byreference, as if fully set forth herein.

This invention is susceptible to considerable variation in its practice.Therefore the foregoing description is not intended to limit, and shouldnot be construed as limiting, the invention to the particularexemplifications presented hereinabove. Rather, what is intended to becovered is as set forth in the ensuing claims and the equivalentsthereof permitted as a matter of law.

That which is claimed is:
 1. A process of preparing propargyl bromide,which process comprises reacting in a reaction zone phosphorustribromide and propargyl alcohol in an inert liquid azeotropic solventthat forms an azeotrope with propargyl bromide, to form a reaction masscontaining propargyl bromide and said azeotropic solvent, and separatinga mixture consisting essentially of propargyl bromide and saidazeotropic solvent from the reaction mass, whereby a stabilizing amountof said azeotropic solvent is present with the propargyl bromide both inthe liquid state and in the vapor phase (i) during the time thepropargyl bromide is being formed and (ii) during and after the timepropargyl bromide is being separated from the reaction mass.
 2. Aprocess of claim 1 wherein said liquid solvent consists essentially of aparaffinic and/or cycloparaffinic hydrocarbon solvent.
 3. A process ofclaim 1 wherein said liquid solvent consists essentially of a mixture ofC₈ paraffinic hydrocarbons.
 4. A process of claim 1 wherein said mixtureconsisting essentially of propargyl bromide and said azeotropic solventis separated from the reaction mass by distillation.
 5. A process ofclaim 4 wherein said liquid solvent consists essentially of a paraffinicand/or cycloparaffinic hydrocarbon solvent.
 6. A process of claim 4wherein said liquid solvent consists essentially of a mixture of C₈paraffinic hydrocarbons.
 7. A process of preparing propargyl bromide,which process comprises bringing together in a reaction zone, componentscomprising phosphorus tribromide, propargyl alcohol, and a stabilizingagent, in the presence of an amine catalyst, wherein a stabilizingamount of said agent is present (i) during the time the phosphorustribromide and the propargyl alcohol are being brought together, (ii)during the time propargyl bromide is being formed, and (iii) during andafter the time propargyl bromide is being separated from by-productsformed in the process, and wherein said stabilizing agent is comprisedof: A) one or a mixture of C₇₋₈ saturated hydrocarbons optionally alongwith up to about 50 wt %, based on the total weight of A), of (1) one ormore C₆ saturated hydrocarbons or (2) one or more C₉ saturatedhydrocarbons, or (3) both of (1) and (2); or B) a mixture of about 10 toabout 90 wt % of one or more C₆ saturated hydrocarbons and about 90 toabout 10 wt % of one or more C₉ saturated hydrocarbons.
 8. A process asin claim 7 wherein at least 95 wt % of said agent is A) or B).
 9. Aprocess as in claim 8 wherein at least 97 wt % of said agent is A). 10.A process as in claim 8 wherein at least 97 wt % of said agent is B).11. A process as in claim 7 wherein up to about 5 wt % of said agent isone or more liquid hydrocarbons other than any hydrocarbon as defined inA) or in B).
 12. A process as in claim 7 wherein up to about 10 wt % ofsaid agent is toluene, one more xylene isomers, one or more non-cyclicethers, tetrahydrofuran, dioxane, beta-ionone, ethanol, or a mixture ofany two or more of the foregoing.
 13. A process as in claim 12 whereinup to about 5 wt % of said agent is toluene.
 14. A process as in claim 7wherein said amine catalyst is a trihydrocarbylamine.
 15. A process asin claim 14 wherein said trihydrocarbylamine is at least one amineselected from the group consisting of triarylamines and trialkylamines.16. A process as in any of claims 7, 8, 9, or 12 wherein propargylbromide together with at least 10 wt % of A) or B) are separated fromsaid by-products by distillation, and remain together with propargylbromide in the condensed distillate, said wt % being based on the totalweight of propargyl bromide and said one or more saturated hydrocarbonsin the condensed distillate.
 17. A process as in claim 16 furthercomprising introducing at least one antioxidant or at least one acidscavenger, or both, into said condensed distillate.
 18. A process as inclaim 17 wherein said at least one antioxidant is at least onesterically hindered phenolic antioxidant and said at least one acidscavenger is at least one epoxide or epoxidized olefinically unsaturatedoil.
 19. A process of preparing propargyl bromide, which processcomprises cofeeding to a reaction zone, components comprising phosphorustribromide, propargyl alcohol, a stabilizing agent, and an aminecatalyst, wherein phosphorus tribromide and propargyl alcohol are fedseparately from each other, and wherein a stabilizing amount of saidagent is present (i) during the time the phosphorus tribromide and thepropargyl alcohol are being brought together, (ii) during the timepropargyl bromide is being formed, and (iii) during and after the timepropargyl bromide is being separated from by-products formed in theprocess.
 20. A process as in claim 19 wherein said stabilizing agent iscomprised of at least about 95 wt % based on the total weight of theagent of: A) one or a mixture of C₇₋₈ saturated hydrocarbons optionallyalong with up to about 50 wt %, based on the total weight of A), of (1)one or more C₆ saturated hydrocarbons or (2) one or more C₉ saturatedhydrocarbons, or (3) both of (1) and (2); or B) a mixture of about 10 toabout 90 wt % of one or more C₆ saturated hydrocarbons and about 90 toabout 10 wt % of one or more C₉ saturated hydrocarbons; or C) toluene,one more xylene isomers, one or more non-cyclic ethers, tetrahydrofuran,dioxane, beta-ionone, ethanol, or a mixture of any two or more of thesecomponents of C).
 21. A process as in claim 20 wherein at least 95 wt %of said agent is A) or B).
 22. A process as in claim 21 wherein at least97 wt % of said agent is A).
 23. A process as in claim 21 wherein atleast 97 wt % of said agent is B).
 24. A process as in claim 20 whereinup to about 5 wt % of said agent is one or more liquid hydrocarbonsother than any hydrocarbon as defined in A) or in B).
 25. A process asin claim 21 wherein up to about 5 wt % of said agent is toluene, onemore xylene isomers, one or more non-cyclic ethers, tetrahydrofuran,dioxane, beta-ionone, ethanol, or a mixture of any two or more of theforegoing.
 26. A process as in claim 25 wherein up to about 5 wt % ofsaid agent is toluene.
 27. A process as in claim 19 wherein said aminecatalyst is a trihydrocarbylamine.
 28. A process as in claim 27 whereinsaid trihydrocarbylamine is at least one amine selected from the groupconsidering of triarylamines and trialkylamines.
 29. A process as in anyof claims 19, 20, or 22 wherein propargyl bromide together with at least10 wt % of A) or B) are separated from said by-products by distillation,and remain together with propargyl bromide in the condensed distillate,said wt % being based on the total weight of propargyl bromide and saidone or more saturated hydrocarbons in the condensed distillate.
 30. Aprocess as in claim 29 further comprising introducing at least oneantioxidant or at least one acid scavenger, or both, into said condenseddistillate.
 31. A process as in claim 30 wherein said at least oneantioxidant is at least one sterically hindered phenolic antioxidant andsaid at least one acid scavenger is at least one epoxide or epoxidizedolefinically unsaturated oil.